Damage effects induced by electrically generated negative air ions in Caenorhabditis elegans
Electrically generated negative air ions (ENIs) have been widely used to improve indoor air quality. However, the effects of ENIs reported so far were inconsistent due to the variance in test systems, end points detected and the exposure methods. In this study, a simple model organism, the nematode Caenorhabditis elegans, was used as an in vivo system to assess the biological effects of continuous ENIs exposure. The worms were exposed to ENIs in a 10(5) 10(5) ions/cm(3) chamber and their development period, lifespan, brood size and germline cell apoptotisis were examined. The results showed that ENIs decreased the development period, shortened the lifespan, increased the germline cell apoptosis and reduced the brood size, suggesting that persistent ENIs exposure might induce damage in C. elegans. To further scrutinize the mechanisms underlying these damage effects, a reactive oxygen species (ROS) sensitive C. elegans, mev-1(kn1) mutant, and sod-3::gfp transgenic strains were used. The results showed that the persistent ENIs exposure significantly shortened the lifespan of mev-1(kn1) mutant compared to the wild type. Moreover, levels of SOD-3 were increased in an exposure time-dependent manner. Treatment with either DMSO or l-ascorbic acid, effective ROS scavengers, could rescue the upregulation of germline cell apoptosis and SOD-3 level induced by ENIs exposure, indicating that ROS may be involved in ENIs exposure-induced damaging effects.